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IS 15497 (2004, Reaffirmed 2010) : Gaseous Fire
Extinguishing Systems--IG 01 Extinguishing Systems. ICS
13.220.10
Jawaharlal Nehru
'Step Out From the Old to the New"
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:<>5&i| mT'5K^5?::5:^>^i»l
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Satyanarayan Gangaram Pitroda
Invent a New India Using Knowledge
Bhartrhari — Nitisatakam
''Knowledge is such a treasure which cannot be stolen"
^'^^^r
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Indian Standard
GASEOUS FIRE EXTINGUISHING SYSTEMS
IG 1 EXTINGUISHING SYSTEMS
1815497:2004
REAFRRiVIED
ICS 13.220.10
© BIS 2004
BUREAU OF INDIAN STANDARDS
MANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG
NEW DELHI 110002
September IQQA Price Group 5
Fire Fighting Sectional Committee, CED 22
FOREWORD
This Indian Standard was adopted by the Bureau of Indian Standards, after the draft fmalized by the Fire
Fighting Sectional Committee had been approved by the Civil Engineering Division Council.
The objective of this standard is to provide to the users of IG 01 systems with specific requirements for the control
of fires of Class A or Class B type. It does not cover the design of explosion suppression systems.
It is important that the fire protection of a building or plant be considered as a whole. IG 01 total flooding
systems form only a part, though an important part, of the available fire protection facilities. It should not be
assumed that the installation of an IG 01 total flooding system necessarily removes the need to consider
supplementary measures, such as the provision of portable fire extinguishers or mobile appliances for first aid or
emergency use, or measures to deal with special hazards.
Controlled inert atmospheres are recognized as effective for extinguishing Class A and Class B fires where
electrical risks are present. Nevertheless, it should not be forgotten, in the planning of comprehensive schemes,
that there may be hazards for which this technique is not suitable, or that in certain circumstances or situations
there may be danger in its use requiring special precautions.
IS 15497 : 2004
Indian Standard
GASEOUS FIRE EXTINGUISHING SYSTEMS
IG 01 EXTINGUISHING SYSTEMS
1 SCOPE
1.1 This standard sets out specific requirements
for the design and installation of total flooding
fire extinguishing systems employing IG 01 gas
extinguishant. This standard is applicable to single
supply as well as distributed supply systems.
1.2 This standard complements various general
requirements applicable to all types of gaseous
fire-extinguishing systems ( Halocarbon as well as
inert gas systems ) listed in IS 15493. As such, both
these standards should be read together before
designing a system. Where requirements in both
the standards differ, this standard shall take
precedence.
1.3 This standard covers systems operating at
nominal pressures of 16 MPaat 15°C and20MPaat
15^Conly.
1.4 Before using IG 01, nature of fire and fire
spread shall be studied for suitability of
extinguishment, as high discharge time of 60 s
may not be suitable for rapid spreading fires.
2 REFERENCES
The standards given below contain provisions,
which through reference in this text, constitute
provisions of this standard. At the time of
publication, the editions indicated were valid. All
standards are subject to revision, and parties to
agreements based on this standard are encouraged
to investigate the possibility of applying the most
recent editions of the standards indicated below:
IS No.
7285:1988
Title
Specification for seamless steel
cylinders for permanent and high
pressure liquefiable gases
{second revision)
15493:2004
Gaseous
systems
requirements
fire
extinguishing
General
3 GENERAL INFORMATION
3.1 Application
3.1.1 IG 01 total flooding system is designed to
develop a controlled atmosphere in an enclosed
space yielding a reduced oxygen concentration
that will not sustain combustion. The appropriate
IG 01 concentration shall also be maintained until
the temperature within the enclosure has fallen below
the re-ignition point.
3.1.2 The minimum TG 01 concentration necessary
to extinguish a flame and the minimum oxygen
concentration necessary to support combustion has
been determined by experiments for several surface-
type fires particularly those involving liquids and
gases. For deep-seated tires, longer soaking times
may be necessary but are difficult to predict.
3.1.3 It is important that residual oxygen
concentrations are not only reached and maintained
for a sufficient period of time to allow effective
emergency action by trained personnel but also
maintained for sufficient period of time. This is equally
important in all classes of fire since a persistent ignition
source can lead to a recurrence of the initial event
once the IG 01 has dissipated.
4 GAS CHARACTERISTICS AND PROPERTIES
4.1 IGOl is a colourless, odourless and electrically
non-conductive gas with a density approximately
1.4 times that of air.
4.2 IG 01 gas shall comply with the specification as
shown in Table I.
4.3 IG 01 system can be used for extinguishing
fires of all classes within the limits specified
in IS 15493.
4.4 IG 01 gas is argon and its specification and
physical properties are shown in Table 2.
4.5 Toxicological information for IG 01 gas are shown
in Table 3.
Table 1 Specification for IG 01
{Clause A.2)
SI No.
(I)
i)
ii)
iii)
Specification
(2)
Purity
Moisture
Requirement
(3)
99.9 percent by volume,
50 ( X ) 10"^ by mass,
Max
Suspended matter None visible
or sediment
IS 15497 : 2004
Table 2 Physical Properties of IG 01
( Clause 4 A )
SI No.
Property
Value
(1)
(2)
(3)
i)
Molecular mass
39.9
ii)
Boiling point at 0.1 MPa
"185.9°C
iii)
Freezing point
-189.4X
iv)
Critical temperature
-122.3"C
V)
Critical pressure
4.9 MPa
vi)
Critical density
536 kg/m^
vii)
Vapour pressure at 20°C
15.2 MPa
viii)
Specific volume of superheated
vapour at 0. 1 MPa and 20X
0.602
Table 3 Toxicological Information for IG 01 Gas
{ Clause 4,5)
SI No. Property Value
(1) (2) (3)
i) No observed adverse effect 43 percent
level (NOAEL)
ii) Lowest observed adverse 52 percent
effect level (LOAEL)
NOTE — These values are the functional equivalents
of NOAEL and LOAEL values which correspond to
12 percent minimum oxygen for the no-effect level
and 10 percent minimum oxygen for the low-effect
level.
4.6 Fill Pressure
The fill pressure of the IG 01 cylinder shall not exceed
the values provided in Table 4 for systems operating
at 16 MPa and 20 MPa respectively.
Table 4 FillPressureoflG 01 Containers
SI No.
System
Property
(1)
(2)
(3)
i)
16 MPa storage
container
Filling pressure at 15^C
ii)
16 MPa storage
container
Maximum container
working pressure at 55°C
iii)
20 MPa storage
container
Filling pressure at 15°C
iv)
20 MPa storage
container
Maximum container
working pressure at 55°C
NOTE — Fig. 1 should be referred for further data on
pressure/temperature relationship
5 SAFETY OF PERSONNEL
In addition to the provisions specified
in IS 15493, the following requirements shall also
apply.
5.1 Protection of Occupants
IG 01 total flooding systems shall not be used
in design concentrations greater than 52 percent
( corresponds to injected concentrations of
74 percent ) in normally occupied areas, unless means
are provided to ensure safe egress of personnel prior
to the discharge of the inert gas mixture.
5.2 In areas, where there is a likelihood of
significant difference between gross and net
volumes of the enclosure, utmost care shall be
exercised in proper system design.
5.3 Though exposure to the concentration levels of
oxygen ( 10 to 15 percent and 2.5 to 5 percent by
volume respectively ) is normally considered to
produce a negligible risk to the personnel, certain
provisions like personnel training, warning
signs, pre-discharge alarms, and discharge inhibit
switch shall be put in place. In addition, adequate
ventilation facilities shall be available to exhaust the
trapped gases following extinguishment process.
5.4 Minimum safety precautions and safety
limits that are associated with the use of IGOl areas
shown in the Tables 5 and 6 below. Since a frre can be
expected to consume oxygen and form decomposition
products, personnel shall treat any fire situation as
an emergency and promptly exit the enclosure.
5.5 Additional provisions as shown in Table 7
shall apply to account for failure of safeguards
( see 5.1 to 5.4 ) to prevent accidental exposures to
the humans present within the enclosure.
6 ENCLOSURE STRENGTH AND VENTING
FACILITIES
6.1 Venting may be provided at levels as high as
possible in the enclosure. Strength and allowable
pressures for average enclosures may be in conformity
with the 6.3.
6.2 The building requirements for the type of
enclosure and free venting required can also be
calculated from the relevant specifications.
6.3 Free venting facilities shall be provided for the
enclosure and the equation for the venting area required
shall be as follows:
where
A = free venting area, in m^;
Q = IG 01 agent discharge rate, in mVmin; and
P = allowable strength of the enclosure, in kPa.
Value of P for various construction types is shown
in Table 8 ( for exceptionally tight enclosures, value
of /* shall be trebled ).
IS 15497 : 2004
260
240
220
200
D
en
D>
u.
05
JQ
^^
180
LJJ
01
D
c/)
(/)
LU
160
CL
140
120
160barat15X
200barat15X
i00i— I — \ — n — I — \ — ] — ] — I — ! — I — I — ] — p
-40-30-20-10 10 20 30 40 50 60 70 80 90 100
TEMPERATURE (X)
Fig. 1 Temperature/Pressure Graph FOR IG 01
Table 5 Minimum Safety Precautions for IG 01
(Clause 5 A)
SI No.
IG 01 Design Concentra
Percent by Volume
tion
Requi
renients
hihibit Switch
Egress in 30 s
Safety Interlock
Lock-off Valve
and Time Delay
Max
(1)
(2)
(3)
(4)
(5)
(6)
i)
Below the NOAEL< 43
Required
Not required
Not required
Not required
ii)
Between NOAEL and LOAEL
Required
Required
Required
Not required
43 and 52
iii)
Above the LOAEL > 52
Required
Table 6 Safety Limits for IG 01
(Clause 5 A)
SI No. Safety Limit
(1) (2)
i) NOAEL
ii) LOAEL
'M^ercentage by volume.
IG 01 Design Concentration'^
(3)
43
52
Residual Oxygen Concentration'^
(4)
12
10
IS 15497 : 2004
Table 7 Human Exposure to IG 01 Agent
( Clause 5,5 )
S! No.
Exposure
IG 01 Agent Concentration ( Percentage
-) .
Up to 43 Between
43 and 52
Between
52 and 62
More than 62
(1)
(2)
(3) (4)
(5)
(6)
i)
Oxygen concentration,
in sea-level equivalent
percent
12 Between
12 and 10
Between
10 and 8
Less than 8
ii)
Status space
Normally Normally
occupied occupied
Normally
occupied
Normally
unoccupied
iii)
Exposure time
Not more Not more
than 5 min than 3 min
Not more
than 30 s
No exposure
permitted
Table 8 Allowable Strength of the Enclosure
( Clause 63 )
SI No.
Construction
Type
Typical Structures
Allowable Load on Enclosure
kPa
(1)
(2)
(3)
(4)
i)
Light
Light weight partitions,, glazing
1.25
ii)
Normal
Brick
2.50
iii)
Vault
Reinforced concrete
5.00
7 EXTINGUISHING AGENT SUPPLY
7.1 Quantity
a) The amount of the IG 01 in the system
shall be at least sufficient for the largest
single hazard protected or group of
communicating hazards that are to be
protected simultaneously.
b) Where required, the reserve quantity shall
be as many multiples of the main supply
as considered necessary. Normaily, 100
percent standby supply is recommended.
c) Where uninterrupted protection is
expected, it is necessary to keep both main
and standby supplies permanently
connected to the distribution piping and
arranged for quick and easy changeover. In
other cases, it is permissible to keep the
standby supply within the protected premises
in accessible locations.
d) The quantity of the IG 01 required shall
be further adjusted to compensate for any
special conditions, such as unclosable
openings, forced ventilation, the free volume
of air receivers that may discharge into the
risk, altitude ( substantially above or below
sea ievel ) or any other causes for the
extinguishant loss.
7.2 Total Flooding Quantity
a) The amount of IG 1 required to achieve the
design concentration shall be calculated
from the following equations and this
figure shall need further adjustment as
stated in 7.1(d):
V 100
M- 2.303
^siogjo
100-C
where
M
C
V -
V -
S ==
b)
total flooding quantity, kg;
design concentration, percent by
volume;
net volume of the hazard, m^;
volume of the structural/similar
permanent objects in the enclosure
that gas can not permeate, m^;
AT, + K^ (7), where K^ and K^ are
constants specific to the agent
used and T is minimum
temperature inside enclosure; and
S^ "= specific volume of superheated
agentat2PC,mVkg;
Specific volume constants for the IG 1 gas
are A^/- 0.799 68 and A^2 = 0.002 93. IGOl is
a non-liquefied gas at 1 60 bars. It may also
be noted that this equation provides an
allowance for the normal leakage from a tight
enclosure.
The agent requirement per unit volume of
protected space can also be calculated by
using the Table 9 for various levels of
SS 15497 : 2004
concentration corresponding to the
temperature within the protected enclosure.
NOTE — Quantity of the agent shaU be the highest
of the values calculated from the provisions
contained in 7.2(a) and 7.2(b).
7.3 The actual quantity of IG 01 gas storage
required and the resultant residual oxygen
concentration produced shall be determined in the
following manner, which shall further subject to
changes for pressure change due to elevation
(^^e 7.3.3).
7.3.1 Enclosure Volumes
The net enclosure volumes are calculated using
the following equations:
K) y = y -V
where
y.. = maximum net volume of the
Max
enclosure, m*^;
V = gross volume of enclosure, m^;
V^ == volume of the structural/similar
permanent objects in the
enclosure that gas can not
permeate, m^;
^Um "^ iTiinimum net volume of enclosure
considering the maximum
anticipated volume of the
occupancy related to the objects,
in the enclosure, m-\ and
J/ = volume of the occupancy related
objects in the enclosure that gas
can not permeate, for example,
furniture fittings, etc, \v?.
7.3.2 IG 01 Parameters
The required IG 01 gas quantity, number of
cylinders, actual injected concentration etc, are
calculated using the following equations:
a) IG 01 agent quantity ( Theoretical )
^th -^MaxX^,
.(1)
A/^,^ = theoretical IG 01 quantity, m^;
^Max "^ rnaximum net volume of the enclosure,
m^; and
C| = appropriate injected concentration.
b) IG 01 containers
The number of containers required shall
be as follows after rounding off as
appropriate :
A^ =Hi/^c .........(2)
N = number of containers;
tV/^,^ = theoretical IG 01 quantity, m''; and
M^ = quantity of IG 1 agent per container,
m^.
Standard containers with standard filling
pressures should be adopted to facilitate
logistics.
c) Actual quantity of IG 01 agent
The actual quantity of the agent is determined
as per the equation below:
M^ - NxM^ ..(3)
M^ ==" actual quantity of IG 1 storage, m\
N = number of containers; and
M == quantity of IG 1 agent per container,
m\
d) Actual IG 01 injected concentration
The actual injected concentration of the agent
based on the actual quantity of the IG 01 agent
storage is calculated as below:
-. (4)
C^j ==^ actual IG 01 injected concentration
M^ = actual quantity of IG 1 storage, m^;
and
^Max ^ maximum net volume of the enclosure,
e) Lastly, it is required to adjust the number of
IG 01 agent containers, where necessary, by
compensating for ambient pressure change
due to location elevation as per 7.3.3 and
round off the number as before. The equation
in such cases will be as follows :
N^ = iVx atmospheric correction factor,
N^ "" adjusted number of containers, and
N = initial number of containers.
7.3.3 Atmospheric Correction Factors
It shall be necessary to adjust the actual IG 01 agent
quantity for altitude effects. Depending upon the
altitude, atmospheric correction factor shall be applied
as per the Table 1 0. The adjusted IG 01 agent quantity
is determined by multiplying the number of IG 01
containers by the ratio of average ambient enclosure
pressure to standard sea level pressure.
8 CONCENTRATION REQUIREMENTS
8.1 Fire Extinguishing Concentration
a) The minimum design concentration of the
IG 01 agent for Class A surface fire
( including electrical and electronic ) hazards
IS 15497 : 2004
Table 9 Total Flooding Quantity (IG 01)
[Clause 1.2(b)]
SI No.
Temp, °C
Specific
Vapour
Volume
mVkg
Mass Req
uirements of IG 01 per Unit Volume of Hazard, kg/Vg,^^,^j,^,^^
Design Concentration ( Percentage by Volume )
C
r
^
T
S
34
38
42
46
50
54
58
62
(1)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
(9)
(10)
(H)
i)
-40
0.479
0.522
0.601
0.685
0.775
0.872
0.976
1,091
1.217
ii)
-35
0.489 3
0.511
0.588
0.671
0.758
0.853
0.956
1.068
1.191
iii)
- 30
0.499 6
0.501
0.576
0.657
0.743
0.836
0.936
1.046
1.167
iv)
-25
0.509 8
0.491
0.565
0.644
0,728
0.819
0.917
1.025
1.143
V)
-20
0.520 1
0.481
0.554
0.631
0.714
0.803
0.899
1.005
1.120
vi)
- 15
0.530 4
0.472
0.543
0.619
0.700
0.787
0.882
0.985
1.009
vii)
- 10
0.540 6
0.463
0.533
0.607
0,686
0.772
0.865
0.966
1.078
viii)
-05
0.550 9
0.454
0.523
0.596
0.674
0.758
0.849
0.948
1.058
■ ix)
0.561 2
0.446
0.513
0.585
0.661
0.744
0.833
0.931
1.038
X)
5
0.571 5
0.438
0.504
0.574
0.649
0.731
0.818
0,914
1,020
xi)
10
0.581 7
0.430
0.495
0.564
0.638
0,718
0.804
0,898
1.002
xii)
15
0.592
0.423
0.486
0.554
0.627
0,705
0.790
0,883
0.984
xiii)
20
0.602 3
0.416
0,478
0.545
0.616
0.693
0.777
0.868
0.968
xiv)
25
0.612 6
0.409
0.470
0.536
0.606
0.682
0.764
0,853
0.951
xv)
30
0.622 8
0.402
0.462
0.527
0.596
0,670
0.751
0.839
0.936
xvi)
35
0.633 1
0.395
0.455
0.518
0.586
0,659
0.739
0.825
0.920
xvii)
40
0,643 4
0,389
0.448
0.510
0.577
0.649
0.727
0.812
0.906
xviii)
45
0.653 6
0.383
0.440
0.502
0.568
0.639
0.716
0.799
0.892
xix)
50
0.663 9
0.377
0.434
0.494
0.559
0.629
0.704
0.787
0.878
xx)
55
0.674 2
0.371
0.427
0.487
0.550
0.619
0.694
0.775
0.864
xxi)
60
0.684 5
0.366
0.421
0.479
0.542
0.610
0.683
0.763
0.851
xxii)
65
0.694 7
0.360
0.414
0.472
0.534
0.601
0.673
0.752
0.839
xxiii)
70
0,705
0.355
0.408
0.465
0.526
0.592
0.663
0.741
0.827
xxiv)
75
0,715 3
0.350
0.403
0.459
0.519
0.584
0.654
0.730
0.815
xxv)
80
0.725 6
0.345
0.397
0.452
0.511
0.575
0.645
0.720
0.803
xxvi)
85
0.735 8
0.340
0.391
0.446
0.504
0.567
0.636
0.710
0.792
xxvii)
90
0.746 1
0.335
0.386
0.440
0.497
0.560
0.627
0.700
0.781
xxviii)
95
0.756 4
0.331
0.381
0.434
0.491
0,552
0,618
0.691
0.770
xxix)
100
0.766 6
0.326
0.376
0.428
0.484
0.545
0.610
0.682
0.760
shall be the extinguishing concentration
29.2 percent and with a loading of 20 percent
as a safety factor (35 percent ).
b) The minimum design concentration of the
IG 1 agent for Class B hazards shall be the
extinguishing concentration ( determined by
Cup Burner test ) with a loading of 30 percent
as a safety factor.
c) Combustible solids — The minimum injected
concentration of IG 01 agent for surface
type Class A risks shall not be less than
40 percent by volume which yields, on a free
efflux basis, a residual oxygen concentration
of 14 percent by volume in the enclosure.
9 APPLICATION RATE AND DISCHARGE TIME
9.1 Rate of Application
The design application rate shall be based on the
quantity of IG 01 ( M^ [ see 7.3.2 (c) ] for the desired
concentration ( see 8.1 ) and for the time allotted to
achieve the design concentration ( see 7.2 ). The
oxygen concentration, however, shall be within the
limits as specified in 5.3.
9.2 Duration of IG 01 Discharge
a) The discharge time period is defined as the
IS 15497 : 2004
Table 10 Atmospheric Correction Factors
{Clausel 3.3)
SI No.
Equiva
ilent Altitude, m
Enclosure Pressure, mm Hg
Atmospheric
Correction Factor
i)
"920
840
1.11
ii)
-610
812
1.07
iii)
-300
787
1.04
iv)
760
1.00
V)
300
733
0.96
vi)
610
705
0.93
vii)
920
678
0.89
viii)
1 220
650
0.86
ix)
1 520
622
0.82
X)
1 830
596
0.78
xi)
2 130
570
0.75
xii)
2 440
550
0.72
xiii)
2 740
528
0.69
xiv)
3 050
505
0.66
time required to discharge from the nozzles
95 percent of the agent mass at 27°C, necessary
to achieve the minimum design concentration
based on a 20 percent safety factor for flame
extinguishment.
b) The minimum theoretical injected
concentration, that is, 34 percent by volume
shall be achieved within 1 min and the actual
injected concentration ( that is the above plus
a suitable safety factor, adjustment for
container rounding off ) shall be achieved
within 2 min, 95 percent of the minimum
design quantity of the agent shall be released
within 60s.
c) Flow calculations performed in accordance
with 12, or in accordance with the listed pre-
engineered systems, shall be used to
demonstrate the discharge time requirements
stated above.
d) For explosion prevention systems, the
discharge time for agents shall ensure that
the minimum inerting design concentration
is achieved before concentration of flammable
vapours reach the flammable range.
e) When an extended discharge is desired to
maintain the design concentration for the
specified period of time, additional quantities
of agent can be applied at a reduced rate. The
initial discharge shall be completed within
the limits as specified above. Performance
of the extended discharge shall be
demonstrated by test.
f) Where containers are situated remote from
the protected enclosure, extended transit time
will be apparent. Authorities concerned shall
be consulted before locating the containers
in such cases.
9.3 Retention Time
Following the discharge of the agent into the
enclosure, at least 80 percent of the design
concentration ( or inerting concentration as the case
may be ) shall prevail when measured after 10 min of
discharge.
10 STORAGE CONTAINERS
The IG 01 storage containers shall comply with the
following in addition to various requirements contained
in IS 15493.
a) The containers used in IG 01 systems shall
be seamless cylinders confirming to IS 7285
designed, fabricated, inspected, certified and
stamped in accordance with the requirements
of Chief Controller of Explosives.
b) The storage containers shall have reliable
means of indicating their pressure.
c) The storage containers shall have reliable
means of indicating the variation of container
pressure with temperature. A pressure/
temperature chart ( see Fig. 1 ) attached to
the container is acceptable.
d) The requirements of authorities having
jurisdiction for containers may take presence
over the requirements of this standard, if their
specifications are more stringent.
11 DISTRIBUTION SYSTEM
The IG 01 distribution system shall comply with the
following in addition to various requirements contained
IS 15497 : 2004
in IS 15493.
11.1 Piping Network
a) The piping shall withstand the maximum
expected pressure at the maximum storage
temperature, as follows:
1) 1 6 MPa systems — 20 MPa at 55X, and
2) 20 MPa systems -— 25 MPa at 55°C.
b) The piping shall withstand the maximum
developed pressure at 55°C and shall be in
accordance with IS 15493.
c) Carbon steel pipes and fittings shall be
galvanized inside and outside or otherwise
suitably protected against corrosion.
Stainless steel pipes and fittings may be used
without corrosion protection.
11.2 Piping Fittings
a) Pipe fittings shall comply with the
requirements given in IS 15493.
b) Fittings shall be selected according to the
wall thickness or schedule number of the pipe
to which they are intended to be fitted.
11.3 Pipe Sizing
Pipe sizing is a complex issue, particularly when too
small a bore results in excessive pressure losses
while two large a bore reduces the flow velocity. This
may also result in excess pressure drops and
lower flow rates. The sizes can be checked using an
approved computer flow calculation programme.
11.4 Nozzle Placement
a) The type of nozzles selected, their number
and placement shall be such that the design
concentration will be established in all parts
of the protected enclosure and such that the
discharge will not unduly splash flammable
liquids or create dust clouds that could
extend the life, create an explosion, or
otherwise adversely affect the contents or
the integrity of the enclosure.
b) Nozzles shall be selected and located to protect
an area less than its area of coverage. The
area of coverage to the type of nozzle shall
be so listed for the purpose.
c) Maximum nozzle height above floor level for
a single row of nozzles is 3 .5 m. Where ceiling
height ( of the protected enclosure ) exceeds
3.5 m, an additional row of nozzles shall be
provided for uniform and faster distribution
of the agent within the enclosure.
d) Minimum nozzle height above the floor level
of the hazard shall be 0.2 m.
e) In case of enclosures having no false
ceiling, nozzles can be located on the ceiling
anywhere within 0.5 to 5 m from the
walls. In case of enclosures having false
ceilings, deflector shields shall be used
with each nozzle and also nozzles shall be
so located ( with an anticipation of
dislodgement of false ceiling materials or
any movable objects in the path of
discharge ) to prevent any damage thereto.
f) Nozzles shall be provided in all the
concealed spaces, floor voids, ceiling voids,
etc, besides the main area within the
protected enclosure.
g) Selecting the number of nozzles in a system
shall take into account, the shape of the
enclosure ( Area and volume ), shape of the
void ( raised floor, suspended ceiling ).
Installed equipment in the enclosure/void
( Chimney effect ), allowed pressure at the
restrictor ( Pipe quality ), obstructions, which
may affect the distribution of the discharged
agent and architectural considerations.
h) In hazards having suspended ceiling,
consideration shall be given for having
nozzles installed in the ceiling void
( simultaneous discharge ) in order to
equalize the pressure during discharge, thus
reducing the risk of unnecessary damaging
ceiling tiles, etc.
j) In hazards having raised floor ( not gas-
tight ) consideration shall be given for having
nozzles installed in the floor void
( simultaneously discharge ) in order to
equalize the pressure and obtain
extinguishing concentration below the
floor.
k) In hazards having suspended ceiling,
nozzles for protecting rooms void shall be
installed in such a way that the jets from the
nozzles do not damage the ceiling plated
excessively during discharge, that is, the
nozzles to be positioned vertically with the
discharge holes free of the ceiling tiles and/
or Escutcheon plates. For light weight ceiling
tiles, it may be recommended to securely
anchor tiles for a minimum of 1,5 m from
each discharge nozzle.
m) It is recommended in enclosures/rooms/
voids with heights up to 5 m to have a nozzle
installed per each 30 m^.
n) The maximum distance between nozzles
should not exceed 6 ra and the maximum
distance to wall/partition should not
exceed 3 m.
IS 15497 : 2004
12 HYDRAULICS OF THE SYSTEM
12.1 An approved hydraulic calculation method
shall be employed to predict pipe sizes, nozzle
pressure, agent flow rate, discharge per nozzle and
the discharge time.
12.2 The various parameters described
in 7.3.1, 7.3.2, 9.1 and 9.2 shall be considered to
determine the following minimum limits of accuracy:
a)
b)
c)
The weight of agent predicted by flow
calculation to discharge from the nozzle
should agree with the total weight of agent
actually discharged from each nozzle in the
system within a range of -5 percent to + 10
percent of actual prediction.
The discharge time predicted by the flow
calculation method should agree with the
actual discharge time from each nozzle in the
system within a range of ± 5 s.
The accuracy of the calculated nozzle
pressures versus actual pressures at each
nozzle should be such that actual nozzle
pressures in an installation will not fall outside
the range required for acceptable nozzle
performance.
The nozzle pressure should not fall below the
minimum or above the maximum nozzle
pressure required for the nozzle to uniformly
distribute the agent throughout the volume
which that nozzle's discharge is to protect.
13 COMMISSIONING AND ACCEPTANCE
TESTING
13.1 Criteria for Acceptance
The completed IG 01 total flooding system shall
be commissioned in accordance with clause 9
of IS 15493 and the system's performance proved by
at least one of the following methods:
d)
a)
It is not normally recommended to
conduct full-scale discharge test of IG 1
total flooding systems. Where the authorities
concerned insist on full-scale discharge test,
the tests shall be conducted in accordance
with 14.
b) Where a full discharge test using IG- 01 is
not insisted by the authorities concerned,
the following procedure shall apply:
1) Subject the distribution system to a
hydrostatic pressure test of 1.50 times
the calculated pipework's maximum
developed storage pressure at 5 5 °C, then
purge the system to remove moisture and
prove free passage.
2) Subject the protected area to an
enclosure integrity test in accordance
with the procedure given in IS 1 5493.
13.2 Commissioning Certification
When the system commissioning is completed
the installation agency shall issue a typical test
certificate.
13.3 Where the system fails to comply with various
provisions as stated above, the fault shall be rectified
and, if necessary, the system retested.
14 IG 01 FULL SCALE DISCHARGE TEST
PROCEDURE
14.1 This shall be in accordance with IS 15493.
14.2 Recommissioning
Restore all systems to a fully operational status.
14.3 Reporting
The following shall be reported:
a) Information identifying the system shall
include:
1) installation, designer and contractor;
2) enclosure identifications;
3) enclosure temperature prior to discharge;
4) oxygen and carbon dioxide residual
concentrations; and
5) position of sampling points.
b) Date and time of test.
c) Discharge time.
d) Concentration levels at each sampling point
at 2 min and 1 min from the commencement
of discharge.
e) System deficiencies.
f) Reference to this test method
(i'^e IS 15493).
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